http://kb.mozillazine.org/Dictionaries
How to install and un-install dictionaries in firefox. Trick is /usr/lib/firefox-VERSION/dictionaries/ (files can be extracted from the xpi).
http://www.quinapalus.com/cgi-bin/match
A great little tool. Give it a vaguely regex like pattern and it'll give you a list of all the possible words. Want 5 letter words ending in me or be, gotcha! Great for domain name inspiration. Output is scripting friendly plain text. :-)
http://www.mobile-webster.com/Series60.html
A bunch of dictionaries for Symbian devices, including Spanish to English. :-)
http://africanlanguages.com/swahili/
Swahili to English / English to Swahili dictionary. Translates individual words, useful for creating names. :-)